sugar, mirin, and gochujang. Mix well until sugar and gochujang are dissolved. Set aside.
Prepare the vegetables by finely chopping the garlic, dicing the onion, and thinly slicing the spring onions and red chili.
Heat a wok or pan over medium-high heat, drizzle 2 tablespoons of vegetable oil, add the onion, and stir-fry until slightly tender. Add the chopped garlic and stir for a few seconds.
Add the ground beef and stir-fry for 3-4 minutes, until almost no longer pink.
Whisk and pour the sauce over the meat and toss everything quickly to combine evenly.
Add the chili slices and spring onions, and continue to stir for another minute.
Turn off the heat and sprinkle toasted sesame seeds.
Transfer to a serving plate and serve immediately over hot steamed rice, topped with extra chopped spring onions and toasted sesame seeds.